libgfortran.so SONAME and powerpc64le-linux ABI changes

[Joseph Myers]

On Mon, 4 Oct 2021, Jakub Jelinek via Gcc wrote:

> One problem with that is that I think IEEE quad long double support relies
> on glibc 2.32 or later, so not sure what exactly would be done if gcc is
> built against older glibc when it needs to call libm routines.  Perhaps
> convert to __ibm128, call the __ibm128 sinl etc. and convert back (big loss
> of precision and range, but at least something).

Using libquadmath functions would be better in that case - arranging for 
libquadmath to be built in this case if it isn't already - than converting 
to __ibm128.

(On the other hand, when _Float128 functions are available in libm, I 
think it would be better for Fortran to call those rather than libquadmath 
functions - *f128 (or the __*ieee128 aliases available on powerpc64le for 
namespace reasons, not sure if those namespace reasons have any relevance 
to Fortran) instead of *q.  See my comments on that in 
<https://gcc.gnu.org/pipermail/gcc-patches/2021-September/578937.html>.)

-- 
Joseph S. Myers
joseph@codesourcery.com